Eumerus intermedius Gilasian & van Steenis, 2022

Gilasian, Ebrahim, van Steenis, Jeroen & Parchami-Araghi, Mehrdad, 2022, Six new species of the genus Eumerus Meigen, 1822 from Iran (Diptera, Syrphidae), Journal of Insect Biodiversity and Systematics 8 (3), pp. 483-512 : 500-503

Eumerus intermedius Gilasian & van Steenis sp. nov. ( Figs 14, 17A, C, E)

https://zoobank.org/ urn:lsid:zoobank.org:act:0C1280FD-E2E3-4262-BFEB-C65339FA1ED3

Differential diagnosis: This species differs from the members of Eumerus ornatus group by the following characters: Eyes short pilose as in E. lucidus Loew, 1848 and E. subornatus Claussen, 1989 ; eye contiguity about two times as long as frontal triangle (in E. subornatus as long as frontal triangle); basoflagellomere rectangular, yellowish-orange with a narrow brown margin dorsally and anteriorly (in E. lucidus oval and entirely yellowish-orange, in E. ornatus Meigen, 1822 nearly square with extended ventral margin and brownish-black and in E. subornatus rectangular with extended ventral margin); ocellar triangle isosceles (in E. lucidus almost equilateral); eye contiguity slightly shorter than in E. ornatus ; thorax white pilose (in E. ornatus extensively black pilose); metafemur rather narrow, entirely yellowish-white pilose (in E. ornatus extensively black pilose on apical 1/4 anteriorly); metatibia pilose, without dense whitish pile (in E. argyropus Loew, 1848 and E. flavitarsis Zetterstedt, 1843 densely white pilose); metatibia white pilose dorsally and apically (in E. subornatus mostly black pilose, with only iridescent white pile apically); yellowish-orange triangular maculae on tergum II whitish pollinose posteriorly ( E. subornatus only with a narrow long white pollinose maculae); pre-genital segment black pilose; cerci enlarged, spherical as in E. subornatus (almost unmodified in E. argyropus and E. flavitarsis while slightly enlarged in E. lucidus and in E. ornatus extremely enlarged).

Material examined. Holotype: IRAN ♂ (glued to a card point), Kermanshah prov., Paveh, Dodan , 35°02′26.7″N 46°09′22.1″E, 16 June 2016, 1500 m, Malaise trap, M. Zardouei ( HMIM) . Paratypes, 7 ♂♂ 4 ♀♀: Same data as holotype , 5 ♂♂ 2 ♀♀ ( HMIM) , 2 ♂♂ 2 ♀♀ ( JSA) .

Etymology: The genitalia characters of E. intermedius are almost identical to those of E. subornatus while otherwise it is found to be superficially similar to E. lucidus . The specific epithet “intermedius ”, which is intended to underscore the relation of the newly described species to both species, is a Latin equivalent word of “intermediate” and a noun in apposition.

Description Male. Body length: 6.0– 7.8 mm; wing length: 4.2–5.5 mm. Head ( Figs 14C, D). Eyes short pilose, holoptic; eye contiguity almost twice as long as frontal triangle; face white pilose, densely covered with white pollinosity; frontal and vertical triangles white pollinose with white and brown pile respectively; frontal triangle 1.3 times as long as vertical triangle; head in frontal view about 4 times as wide as face; ocellar triangle isosceles, shiny black and brownish pilose; distance between posterior ocelli and posterior margin of eye about 1.4 times as long as ocellar triangle; occiput grey pollinose; frontal triangle 1.4 times as wide as ocellar triangle; vertex at posterior corner of eyes about 1.3 times as wide as vertex over posterior ocelli; head in dorsal view 5.3 times as wide as vertex at posterior corner of eyes; antenna orange, arista brown; basoflagellomere rectangular, yellowish-orange with a narrow brown margin dorsally and anteriorly; arista 1.5 times as long as basoflagellomere ( Fig. 14E). Thorax. Scutum and scutellum shiny black; scutum with two median wide pollinose vittae, white pilose ( Fig. 14A); scutellum with marginal rim; pleurae shiny black, covered with whitish pile except for bare meron and katepimeron; metasternum pilose. Legs. Short yellowish-white pilose; femora mostly brownish-black, orange apically; protibia and mesotibia black in apical half, metatibia black in apical 2/3; protarsus and mesotarsus orange, metatarsus brown dorsally and orange ventrally; metafemur rather narrow, about 3.5 times as long as wide ( Fig. 14F), ventral pile short and about ¼ times as wide as metafemur; anteroventral and posteroventral margins of metafemur with an apical row of 5 and 6 black setae respectively; metatibia without dense whitish pile. Wing. Hyaline; entirely microtrichose; calypters yellowish-white; halter yellowish-orange. Abdomen ( Fig. 14G). Predominantly brownish-black with short whitish pile; yellowish-orange triangular maculae on tergum II with whitish pollinosity posteriorly; tergum III with a pair of orange oblique maculae with white pollinosity; tergum IV with a pair of narrow oblique grey maculae; sternum IV squarish, with a median V- shaped incision posteriorly ( Fig. 14H). Male genitalia. Hypandrium simple; aedeagal apodeme in lateral view as in Fig. 17E; epandrium, cercus, posterior and anterior lobes of surstylus as in Figs 17A, C.

Female. Body length: 6.3–8.2 mm; wing length: 5.0– 6 mm. Similar to the male except for the sexual dimorphism and for the following characteristics: Distance between posterior ocelli and posterior margin of eye about 1.1 times as long as ocellar triangle; vertex with 2 lateral whitish pollinosity behind the posterior ocelli; head in dorsal view 4.5 times as wide as vertex at posterior corner of eyes.

Distribution. Iran.

Remarks. The type material of the similar species as given in the diagnosis was not available for this study. The papers on Eumerus ( Stackelberg, 1961; Claussen, 1989; Claussen & Standfus, 2017; Grković, 2018; van Steenis et al., 2019) and specimens from the collection JSA were used to identify this species.